ase 8 - engine performance - ccbc faculty...

ASE 8 - Engine Performance

Module 15Tech 2 Familiarization

AcknowledgementsGeneral Motors, the IAGMASEP Association Board of Directors, and Raytheon ProfessionalServices, GM's training partner for GM's Service Technical College wish to thank all of thepeople who contributed to the GM ASEP/BSEP curriculum development project 2002-3. Thisproject would not have been possible without the tireless efforts of many people. Weacknowledge:

• The IAGMASEP Association members for agreeing to tackle this large project to createthe curriculum for the GM ASEP/BSEP schools.

• The IAGMASEP Curriculum team for leading the members to a single vision andimplementation.

• Direct contributors within Raytheon Professional Services for their support of translatinga good idea into reality. Specifically, we thank:

– Chris Mason and Vince Williams, for their leadership, guidance, and support.– Media and Graphics department under Mary McClain and in particular, Cheryl

Squicciarini, Diana Pajewski, Lesley McCowey, Jeremy Pawelek, & Nancy DeSantis.– For their help on the Engine Performance curriculum volume, Subject Matter

Experts, John Beggs and Stephen Scrivner, for their wealth of knowledge.

Finally, we wish to recognize the individual instructors and staffs of the GM ASEP/BSEPColleges for their contribution for reformatting existing General Motors training material, addingcritical technical content and the sharing of their expertise in the GM product. Separatecommittees worked on each of the eight curriculum areas. For the work on this volume, wethank the members of the Engine Performance committee:

– Jamie Decato, New Hampshire Community Technical College– Lorenza Dickerson, J. Sargeant Reynolds Community College– Marvin Johnson, Brookhaven College– Jeff Rehkopf, Florida Community College at Jacksonville– David Rodriguez, College of Southern Idaho– Paul Tucker, Brookdale Community College– Kelly Smith, University of Alaska– Ray Winiecki, Oklahoma State University - Okmulgee

ContentsModule 15 – Tech 2 FamiliarizationAcknowledgements .......................................................................................... 2Introduction ...................................................................................................... 4Objectives ........................................................................................................ 4

Overview ......................................................................................................................... 5Central Processing Unit (CPU) ....................................................................................... 6Memory ........................................................................................................................... 7Input Interface ................................................................................................................. 7Output Interface .............................................................................................................. 7DLC Terminal Identification ............................................................................................. 8Features .......................................................................................................................... 9Getting Started .............................................................................................................. 16Connections .................................................................................................................. 17Using The Tech 2 On Vehicle ........................................................................................ 18Diagnostic Trouble Codes (DTCs) ................................................................................ 20Diagnostic Test Status................................................................................................... 23Freeze Frame/Failure Records (only on OBD II vehicles) ............................................ 24Clear DTC Information .................................................................................................. 25Capture Info .................................................................................................................. 26System Information (I/M Flags) ..................................................................................... 34The Service Programming System ............................................................................... 35Tool Options .................................................................................................................. 36The Tech 2 Update Procedure ...................................................................................... 37

© 2002 General Motors CorporationAll Rights Reserved

ASE 8 - EnginePerformance

Module 15 - Tech 2Familiarization

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Student WorkbookIntroduction

ObjectivesAt the end of this section, the technician will be able to do the followingtasks:NATEF Tasks: Area VIII. A.3. Locate and interpret vehicle and major component identification

numbers (VIN, vehicle certification labels, and calibration decals).NATEF Tasks: Area VIII. B.1. Retrieve and record stored OBD I diagnostic trouble codes;

clear codes.2. Retrieve and record stored OBD II diagnostic trouble codes;

clear codes.5. Check for module communication errors using a scan tool.7. Obtain and interpret scan tool data.

STC Tasks:• Install PCMCIA cards correctly and demonstrate proper handling• Customize Tech 2 display; language, contrast, date, time• Navigate through Tech 2 menus using pick lists• Use soft keys to select features• Gather live Scan Data using the Tech 2• Customize data display parameter lists• Capture data using the Quick Snapshot feature• Use the Tech 2 context sensitive Help function• Read and Clear Diagnostic Trouble Codes (DTCs) using Tech 2• Load and replay snapshots• Plot stored data using the Tech 2• Exercise control module outputs using the Tech 2 Special Functions• Make proper connection to PC• Update Tech 2 software• Copy Tech 2 software from one PCMCIA card to another• Program vehicle control modules• Perform Tech 2 self tests




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Student WorkbookOverviewAt the end of this section the technician will understand the features ofthe Tech 2.

The Tech 2 (Figure 15-1) is a hand held diagnostic computerdesigned specifically to help you diagnose and repair electronicsystems used on most late model General Motors vehicles.When attached to the vehicle to be tested, the Tech 2 can be a veryversatile tool. With its large, easy to read display, the Tech 2 guidesyou step by step through the testing procedures. You respond tothe Tech 2 through the keypad commanding it to:• Conduct the test you want to run• Retrieve the diagnostic data you want• Control the function you want to monitorThe Tech 2 gets its power from the vehicle being tested and talks or"interfaces" with the vehicle electronic systems through the DataLink Connector (DLC) located on the vehicle. When connected tothe DLC, the Tech 2 can read Diagnostic Trouble Codes (DTC) anddiagnostic data. The Tech 2 can be adapted to interface with moston board computer systems used on late model GM vehiclesequipped with a DLC. Depending on the application selected, theTech 2 can also control some systems for troubleshooting orautomatic testing.

Figure 15-1, Tech 2 Components




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Student WorkbookBefore detailing the actual operation of the Tech 2, it is necessary tounderstand some basic computer and serial data principles.

What is a computer?A computer is made up of several components (Figure 15-2). It containschips (integrated circuits) to store information, a clock generator tosynchronize all the signals moving from chip to chip inside the computer,and the Central Processing Unit (CPU), which is the brain of the computer.

Figure 15-2, Basic Computer Chips and Circuits

Central Processing Unit (CPU)The CPU is the "brain" of the computer. It is a microprocessor thatperforms calculations and controls system operation. Much like an enginein a car, the CPU is the overriding determinant of system power andspeed. In fact, computers are generally rated according to the clock speedand processing power of the CPU.• CPU speed is rated in megahertz (MHz). The higher the number, the

faster the microprocessor.• Processing power is a rating of how much information the CPU can

process at one time. Again, the higher the number, the better theperformance. Virtually all of today's CPUs are 32 bit or 64 bitmicroprocessors.




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Student WorkbookMemoryComputer memory is of two general types: RAM (Random AccessMemory) and ROM (Read Only Memory).Random Access Memory (RAM) is what the CPU uses to temporarilystore and recall the data required to run the operating system andapplication software. When the computer is turned on, the operatingsystem is loaded into RAM. As applications and files are opened, they tooare loaded into RAM. When the CPU is called upon to perform tasks, itaccesses the information stored in RAM. When an application or file isclosed, it is deleted from RAM.Ram is "volatile," meaning it is wiped clean whenever the computer isturned off. RAM is generally measured in quantities of megabytes (MB)(for example, 16MB or 32MB). Again, the higher the number the better –more RAM means the computer can do more things at once and, as a ruleof thumb, can generally do them faster.

(Read Only Memory) ROM stores the most basic operating instructions ofthe computer. Without ROM, the computer wouldn't even be able to startup. ROM is permanent, or "nonvolatile" it is not erased when the computeris turned off or unplugged.

Flash EPROM is a memory chip inside the computer that can beelectronically erased when software needs to be changed (repaired) orupdated. When "Flash" programming this type of memory chip, the entirememory is erased before the new software is loaded.

Input InterfaceInput interface circuitry receives signals from input devices and convertsthem into digital signals that the CPU (microprocessor) can understand.Some input signals require more conversion than others before they aresent to the CPU for processing (i.e., analog signals require moreconversion than digital signals).

Output InterfaceOutput interface circuitry takes data from the CPU and converts it into aform that can be used outside of the computer (i.e., converts a datacommand from the CPU into a PWM command signal to drive aPCM output).An open in the main line of a parallel circuit (Point A) will also affect allloads in the circuit, while an open in one branch of a parallel circuit(Point B) will only affect loads on the branch in which the open occurs.




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Student WorkbookDLC Terminal IdentificationThe various on board controllers interface with the Tech 2 through theDLC. Examples of such controllers are the :EBTCM Electronic Brake and Traction Control ModuleBCM Body Control ModuleSDM Sensing Diagnostic Module (S.I.R.)ECM Electronic Control ModulePCM Powertrain Control ModuleTCM Transmission Control ModuleVCM Vehicle Control ModuleThe DLC connector allows access to monitor data and control some of thecontroller's operations (Figure 15-3). The Tech 2 reads the serial datasignal from the DLC connector and translates it into the informationprovided on the Tech 2 display screen.

Figure 15-3,12 Pin DLC, 16 Pin DLC




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Student WorkbookFeatures

SizeThe Tech 2 is about 12" x 6" x 2" and weighs 2.2 lbs (Figure 15-4). Thisweight is about the same as the Tech 1.

PowerfulThe Tech 2 is designed to work for many years to come. Because it ismore powerful than the Tech 1, it will be able to help you diagnosevehicles for the foreseeable future.In the past, as communication from the various controllers evolved, eithernew tools were created or adapters were created. The Tech 2 is designedto evolve with the vehicle. Because the Tech 2 uses a VehicleCommunication Interface (VCI) as an adapter to the DLC, the tool can beupdated by a change of the VCI module. This allows hardware updating ofthe Tech 2 without requiring adapters such as the Vehicle InterfaceModule (VIM) which was used by the Tech 1.

Figure 15-4, Tech 2 Features




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Student Workbook

The screen is divided into five areas (Figure 15-5). By looking at theinformation which is displayed in each area, the user may more efficientlyuse the Tech 2.• Title area• Message area• Display/select area• Full text area• Soft key areaThe "full text" area lists a complete description of the highlighted line in the"display/select" area.

Figure 15-5, Tech 2 Screen Areas




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Student Workbook

The keypad of the Tech 2 contains 27 keys (Figure 15 -6). Within thesekeys are 23 keys which are pre-defined and 4 keys which are referred toas "Soft" keys. The soft key usage will change depending on which part ofan application is being used. Following is a definition of the key usage forthe pre-defined keys.

Selection KeysThe four arrow keys are used for screen movement to make a selection.The Up and Down arrows move the highlight bar one line at a time. If theyare held, the highlight bar will scroll. The Left and Right arrow keys willmove the highlight a page at a time. The Left arrow moves the highlight up(previous page) and the Right arrow moves the highlight down (nextpage). The arrow keys are used to move the highlight bar to a position tomake a selection, or to move the display to allow more information to beviewed.

Action KeysThere are a group of keys which are referred to as "Action" keys. As thename implies, action keys will make an action take place on the Tech 2.The action keys are Yes, No, Enter, and Exit.• Yes - Confirms a positive response to a question.• No - Confirms a negative response to a question.• Enter (2 keys) - Indicates a selection has been made.• Exit (2 keys) - Returns user to a previous menu selection.

Figure 15-6, Keypad Layout




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Student WorkbookFunction KeysThe Function keys (FO - F9) allow direct selection of a choice from amenu.

Help keyHelp (?) accesses a tool help function which is specific to the currentinformation being viewed on the Tech 2.

Control KeysThere are two keys which are used to control the Tech 2 itself. These arethe Shift and Power keys. The Shift key will access screen contrastcontrol. To adjust contrast during the current power cycle of the Tech 2,use the following procedure:• Press the Shift key (The yellow light will turn on).• Use the Up arrow to increase screen brightness and contrast or the

Down arrow to decrease screen brightness and contrast.• Press the shift key (the yellow light will turn off).This procedure will only adjust the contrast for the duration of this powercycle of the Tech 2. If the power is turned "off" and then back "on" again,the contrast will change to a default value. The default setting will becovered later in this course book.

Important:If the yellow shift light is "on," only the Power, Shift, Exit and Arrow keysare active.

Some GM dealerships that are dual with non-NAO makes such as Saabor Isuzu may need two PCMCIA cards installed in their Tech 2. When twoPCMCIA cards are installed, the user can command the Tech 2 to switchbetween the two cards by pressing the shift key, then the right or left arrowkey. The Tech 2 must be on the title screen to perform this function. Makesure you press the shift key to deactivate it after completing the switch.There is a Power switch which turns the Tech 2 on and off. A greenindicator will illuminate when the Tech 2 is switched "on."




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Student WorkbookSoft KeysThere are four keys on the Tech 2 which change usage within anapplication. Soft key functions are software driven. This means that the"Soft" key function may change in different areas of the software. The leftmost soft key at the Main Menu will be used to "Clear Vehicle", while inSnapshot the same key position may change Units. The ability for the softkeys to perform different tool operations at different times increases theversatility of the Tech 2.

Thumb ActionThe Tech 2 is designed for one handed operation. The unit is balanced toallow one hand to comfortably hold and operate the tool. Straps on thesides of the tool are adjustable to help hold the Tech 2 in one hand. Thekeypad configuration is designed for thumb usage while holding the tool ineither the left or right hand. It is easier to use the selection and action keysinstead of the function keys as some Tech 2 screens require makingselections from a list on the screen. In these cases there may not be afunction key equivalent.




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Student Workbook

Figure 15-7, PCMCIA Card

The Tech 2 uses a Personal Computer Memory Card Industry Association(PCMCIA) standard memory card for storage of diagnostic functions andapplications (Figure 15 -7). The original memory card had a capacity of10 Megabytes which was ten times the amount of memory that the Tech 1Mass Storage Cartridge (MSC) had. The current memory card has acapacity of 32 Megabytes and is required to use the latest Tech 2software. Because there is more memory, there is storage capability fortwo snapshots and one capture information event. This will improvediagnostic capability for intermittents.The PCMCIA card is accessed through a door on top of the unit, andshould only be removed when required. The card is ejected by pushingthe arrow button pointing to the card to be removed. Cards are notched toallow insertion only one way. When re-inserting the card make sure that itfully seats into the Tech 2. The PCMCIA card fits into slot zero which isclosest to the screen. There is a second slot identified as slot one to beused by dealers dualed with non-NAO makes such as Saab and Isuzu.See page 15-11 for dual PCMCIA card operating instructions.




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Student WorkbookNotice:The PCMCIA card is sensitive to magnetic and static electricity, so careshould be taken when handling the card to prevent damage.A write protect slide mechanism is on the top edge of the PCMCIA card.The correct position is to the middle of the card (unlocked). If the writeprotect is in the locked position, snapshots and capture information will notbe able to be stored, and Service Programming will not work.As was done previously on the Tech I and Mass Storage Cartridge (MSC),the Tech 2 and PCMCIA card will be updated by connecting to a TechlineTerminal or PC.The software that operates the Tech 2 is stored on the PCMCIA card. Thecontents of the card are not distinct applications as was the case with theTech 1 and MSC. All of the applications share a single database ofinformation on the Tech 2's PCMCIA card.




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Student WorkbookGetting StartedThe "Getting Started" application is a built in lesson to show how to usethe Tech 2 (Figure 15-8). The "Getting Started" application is divided intosections to allow easier usage. Inside the application is also an exampleof diagnostic software so that operation of the tool can be practiced whileaway from the vehicle. It is suggested that technicians review the materialincluded in the "Getting Started" application to familiarize themselves withTech 2 operation.

Figure 15-8, Getting Started

Getting Started has the Following Features:FO: Tool Controls - contains information on:• Help keys• Keypad layout and function• Setting screen contrast• Soft keysFl: Hardware - contains information on:• Screen display• VCI module removal• PCMCIA card removal and installation• Cables/adapters and power connections• Prop rod and hand straps• RS232 and RS485 portsF2: Tech 2 Features - contains:• A sequence of Tech 2 screens from a fictitious vehicle that can be

used to learn how to navigate through various Tech 2 screens.F3: Programming Tech 2 - contains information on:• How to connect the Tech 2 to the PC for an update (Software

Download).




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Student WorkbookConnectionsTo use the Tech 2, proper connections will need to be made (Figure 15-9).These connections include power and the DLC. To power the Tech 2 froman OBD II vehicle, simply connect the Tech 2 DLC cable to the vehicleDLC. On a non-OBD II vehicle, or if using the Tech 2 away from thevehicle, another source of power should be used. On vehicle powerconnection may also come from the cigar lighter adapter or from thebattery clip adapter. Using one of the adapters, connect to the jack at theback of the DLC cable connection.The 12 volt adapters have fuses in them to help protect the Tech 2 wiring.The Tech 2 110 volt adapter should NOT be used while the Tech 2 isconnected to a vehicle as data errors may occur. Instead, the AC poweradapter is designed to be used while away from the vehicle, such as at aTechline Terminal or PC. Power supplies of Techline Terminals are notdesigned to support Tech 2 power needs. Therefore, do not use the cigarlighter adapter while at a Techline Terminal. The Tech 2 will work between8 and 20 volts and draws about .75 amps.

Figure 15-9, Tech 2 Connections




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Student Workbook

Using an ApplicationThe vehicle ignition should be "on" before selecting the model year,vehicle type and system. This is critical because on some vehicles theTech 2 will communicate with the controller to determine what optionsare available (i.e., AIR pump or no AIR pump, etc.). In some cases, if thekey is not on when the Tech 2 attempts to gather this information, it willresort to using a default setting that may not be correct for the vehicle youare diagnosing.Once a selection has been made from the Main Menu by either using afunction key or by using the arrow keys to highlight a menu choice andpressing enter, you will then need to supply some additional informationto the Tech 2 (Figure 15-10). This requires navigation through a series oflists (called picklists). On some menus or picklists, the user can use afunction key to make a menu selection, but most of the picklists requireusing the selection and action keys. If a mistake is made in the selectionprocess, or if a different application or function is desired, press "Exit" toback up one level.Within an application, there may be soft keys available for use. These softkeys allow access to additional tool functions without exiting a current toolfunction. Soft keys are made up of sets which will appear together. To seethe next set of soft keys, select the "More" soft key.Although most of the applications/screens described in this book arePowertrain related, the Body and Chassis screens follow the Powertrainformat. For example, the DTC, data list and snapshot screens forBody and Chassis follow the same general format as the equivalentPowertrain screens.

Using The Tech 2 On Vehicle




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Student Workbook

Figure 15-10, Tech 2 Menus (Picklists)




15-20

Student WorkbookDiagnostic Trouble Codes (DTCs)Within each of the Diagnostic applications (Powertrain, Body, Chassis) isa menu choice for DTCs. The DTC menu selection allows the technicianto analyze information about trouble code(s) (Figure 3-5). The screensshown in Figures 3-5 through 3-9 are screens that might be seen on anOBD II, Class 2 vehicle. Not all menu choices will be available on allvehicles or systems.DTC Information (Display of codes) - Each code has it's own page ofinformation. If multiple codes are set, the user must page through thedisplay of codes. The number of codes set will be displayed in the lowerright corner of the screen.When viewing a screen that is displaying a DTC, three categories ofmessages will be displayed under the DTC. The information displayed ineach message will be valuable when diagnosing the owner's concern:Last Test: The results of the last on-board test will be displayed as"passed", "failed", or "not ran". "Not ran" is displayed when the last teststatus cannot be determined.

This Ignition: This parameter will display "passed", "failed", "pass andfail", or "MIL requested."• "Passed" means that the diagnostic test has reported a passing result

with no test failures.• "Failed" means that the diagnostic test has reported a failing result with

no test passes.• "Pass and failed" means that the diagnostic test has reported both

passing and failing results on this ignition cycle.• "Not ran" means that the diagnostic test has not reported or has not

run on the current ignition cycle.• "MIL requested" means that the diagnostic test is requesting the MIL or

SVS lamp to be illuminated.




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Student WorkbookSince Clear: This parameter will display "passed", "failed", "pass andfailed", "not ran", or "history."• "Passed" means that the diagnostic test has reported a passing result

with no test failures.• "Failed" means that the diagnostic test has reported a failing result with

no test passes.• "Pass and failed" means that the diagnostic test has reported both

passing and failing results since DTC's were cleared.• "Not ran" means that the diagnostic test has not reported or has not

run since codes were cleared.• "History" means that the diagnostic test has reported a valid fault since

codes were last cleared.

Figure 15-11, DTC Information




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Student Workbook

Figure 15-12, Specific DTC and Not Ran Since Code Cleared

The Specific DTC feature (Figure 15-11), found under the DiagnosticTrouble Codes (DTC) menu, allows the technician to view informationunique to a single stored DTC. When the technician enters the number ofthe desired DTC and presses Enter, the Tech 2 will display informationrelated to the DTC.The “Not Ran Since Code Cleared” feature (Figure 15-12), displays DTC'sthat have not met the PCM enable criteria and therefore have not run theon-board diagnostic test.




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Student WorkbookDiagnostic Test StatusThis selection displays the test status of all DTCs (Figure 15-13). It showsthe DTC number, whether the test has run or not, and the pass/fail status.This only applies to OBD II vehicles with Class 2 serial data.

Figure 15-13, Diagnostic Test Status




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Student WorkbookFreeze Frame/Failure Records (only on OBD II vehicles)Freeze Frame and Fail Records are "snapshots" (one frame of data each)that are automatically stored by the PCM when certain on-boarddiagnostics report a failure (Figure 15-14). When troubleshooting adriveability concern involving a DTC, Freeze Frame and Fail Records willdisplay data parameters that were present when a fault was detected.These data parameters can help pinpoint the fault. Since Freeze Frameand Failure Records are only one frame of data, they do not have thenavigation and graphing capabilities that the Snapshot feature does.

Figure 15-14, Freeze Frame/Failure Records




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Student WorkbookClear DTC InformationThe Clear DTC Information feature is mainly used after making a repairassociated with a stored DTC (Figure 15-15). When the technician selectsthis feature, all stored DTCs will be erased, I/M Flags, DTC Information,Freeze Frame, and Fail Records will also be cleared/erased. Selecting thisfeature will also extinguish the MIL.

Figure 15-15, Clear DTC Information

Important:When diagnosing an owner concern, do not select the Clear Informationfeature until the repair has been completed and verified. You will losevaluable diagnostic data if this feature is activated too soon.If your diagnostic procedures require you to Clear Information (ordisconnect the battery), use the Capture Info feature to save diagnosticdata before clearing information.




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Student WorkbookCapture InfoThe Capture Info feature is used to store PCM diagnostic information(DTC Info, Freeze Frame, and Fail Records) in the Tech 2. This feature isused when the technician needs to save vital data for review later. CaptureInfo is commonly performed before disconnecting the battery or clearingDTC information. Only one Capture Info can be stored in the Tech 2 at atime (Capture Info consists of one page of DTC Info for each DTC storedin the PCIVI, maximum of one Freeze Frame, and up to five FailureRecords*). If a Capture Info is stored in the Tech 2 and the technicianattempts to retrieve a new one, the current one will be erased andreplaced with the new one. Figure 15-16 shows the progression ofscreens involved in the Capture Info process.

Figure 15-16, Capture Info




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Student Workbook

The Tech 2 Data Display feature displays data parameters for thecontroller being diagnosed (Figure 15-17). Data parameters may bedivided into multiple data lists, so be sure to use the service manual todetermine which list will display the information needed. While using DataDisplay, use the arrow keys to display and review the entire data list. TheDisplay area is truncated at 23 characters, so to see all of the text to bedisplayed, highlight the parameter in question and look at the full text areaof the display.There is a "counter" in the lower right hand corner of the Tech 2 screen(just above the "More" soft key) that shows the highlight bar position inrelation to the total number of data parameters on the list. For example, inFigure 15-17 the counter displayed is 1/24, indicating that the highlight baris on the first data parameter and there are 23 more parameters availablefor viewing.While using Data Display, the user has the ability to lock up to fiveparameters within the display area. The five locked parameters remain atthe top of screen even if the display is scrolled. To lock parameters, pressthe Select Items soft key. On the picklist that will appear, move thehighlight bar to the item to be locked and press the "Enter" key. After allitems desired have been selected, press the "Exit" key to return to theData Display. To modify a locked list, choose the "Select Items" soft keyand select the parameter a second time to clear it. Use the "Clear All" softkey to clear all the locked parameters.While in the 'Data Display function, the user may display codes directlyfrom Data Display by pressing the DTC soft key.

Figure 15-17, Data Display Screen




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Student WorkbookTech 2 allows the user to take a snapshot while in the Data Displayfunction. This is done by selecting the "Quick Snapshot" soft key. Thesnapshot will have a beginning trigger point. This snapshot will displaceone of the previously stored snapshots on the Tech 2. Quick Snapshotdoes not store any DTC information with the snapshot. More informationon using Snapshot is found later in this section.By selecting the "More" soft key, additional functions become available.The "Units" soft key allows switching between English and Metric displays.Other useful functions are the "Previous List" and "Next List" soft keys.These soft keys allow switching between various available Data Displaylists without needing to "Exit" and select a different list.




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Student Workbook

Figure 15-18, Special Functions

The Special Functions menu selections (Figure 15-18) allow access tooutput controls and other special tests. Other special tests may includethe ability to perform system resets (such as Fuel Trim Reset), or toperform ABS Auto Bleed procedures.After selecting Special Functions, a list of tests available for theprogrammed vehicle will be displayed. After one of these tests isselected, any special instructions to set up for the test will be displayed.The next display will show a list of data parameters along with Soft keyswhich will allow the test to be performed.Special Function tests are used to control solenoids or other devices thatthe vehicle on-board computer controls normally. When the techniciancommands the device on, the vehicle computer is commanded to turn iton regardless of what inputs would normally be needed to activate thedevice. This can help determine where a fault is occurring in the system.




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Student Workbook

Figure 15-19, Snapshot Screens




15-31

Student WorkbookA Snapshot is a Tech 2 recording of data the controller was receiving whilethe snapshot was being made (Figure 15-19). A snapshot may be used toanalyze the data that was occurring during the time a vehicle conditionwas happening. This allows the technician to concentrate on making thecondition occur, rather than trying to view all the data in anticipation of thefault. The snapshot will contain information around a trigger point that thetechnician has selected. Only a single Data List may be recorded in eachsnapshot. The Tech 2 has the ability to store two snapshots. The ability torecord two snapshots allows comparing hot/cold or good/bad vehiclescenarios. These snapshots are stored on a "first in, first out" basis. If athird snapshot is taken, the one that had been stored in the PCMCIAmemory first will be lost.Snapshots can be one of two types:• Snapshot - taken from the Snapshot menu choice• Quick Snapshot - taken from the Quick Snapshot soft key choice

(available in Data Display Mode)When a snapshot is taken, it is recorded onto the PCMCIA memory card.A tone will sound at the beginning and end of the snapshot. Because thesnapshot is recorded onto the memory card, snapshots are not lost if theTech 2 is powered down.After the snapshot menu choice has been selected, some set-upselections must be made. These choices include engine or transmissiondata list, Trigger Type and Trigger Point.The Trigger Type menu selection will determine what must happen tocause the snapshot to trigger. The trigger of the snapshot will happenbased on one of three occurrences, Any Code, Single Code or ManualTrigger. The Any Code mode will trigger a snapshot whenever any troublecode is stored. (This is when the first code is stored in the vehiclecontroller memory.) Single Code Snapshot mode will cause a snapshot tobe taken when a user specified trouble code is stored. Manual trigger willcause a snapshot to be taken based on the user pressing a soft key totrigger the snapshot. Manual trigger can also be used while in the AnyCode or Single Code modes of snapshot.




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Student WorkbookTrigger Point refers to the point in a snapshot which represents a codeoccurring or a manual trigger occurred. This will help the technician toknow at what point in the snapshot to look for changes in the dataparameters. Trigger Point may be set for Beginning, Center, or End. TheBeginning choice will cause the Tech 2 to start recording information fromthe trigger point and continue on until the snapshot storage area is full.This choice is useful if the fault is predictable in it's nature. Center triggerpoint is used most commonly because it allows data to be stored frombefore the trigger point as well as after the trigger point. This allowscomparing data from before, during, and after a fault has happened. Thethird type of trigger is End. The eng trigger type is used if the technicianwants the trigger to stop the Snapshot recording. This could be useful ifthe technician is occupied during the fault and wants to cause thesnapshot to end after the fault has occurred. End trigger point containsonly information that happened prior to the Snapshot being triggered.After the choices have been made, the technician will select the RecordSnapshot soft key (Figure 15-19), then a display of current vehicle data ispresented. This data list may be manipulated the same as in the DataDisplay menu selection.The technician should now attempt to recreate the owner's concern. Whenthe condition occurs, the technician should immediately press the "trigger"soft key. After the snapshot has been triggered, the Tech 2 will begin tostore the snapshot onto the PCMCIA memory card. The amount of timethe snapshot will record depends on the vehicle/ controller you arediagnosing. At times, the snapshot will record longer than is needed fordiagnosis. If this happens, press the exit key to stop the snapshot early.When the snapshot is stopped (either automatically or manually) a screenwill appear that displays the "trigger type" of the snapshot. Press the"continue" soft key to display frame 0 of the stored snapshot.If the technician exits the replay of data he will have the ability to eithermake another Snapshot, Exit, or Replay a previously recorded snapshot. IfReplay is selected from the menu, the technician must select from the twoavailable Snapshot choices. The previously recorded snapshot will beidentified by the date and the time the snapshot was made. It is importantthat the clock in the Tech 2 is set to the correct time so it is easy to identifywhich snapshot you want to diagnose.




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Student WorkbookWhile replaying a snapshot, the technician will use the normal DataDisplay control functions to view the data from a particular moment in time(Figure 15-14). To look at the data that was happening at a different timeframe, soft keys will be used. A variety of movement capabilities areavailable when the soft keys are used. The ability to move Frame byFrame, either Forward or Backward, is one method of moving within thesnapshot. By selecting the "More" key, the technician will have access toother soft key functions such as:• Auto Forward• Auto Reverse• Select Items• Select Frame• Trigger Frame• First Frame• Plot• Stop• Last Frame• Units• Previous Frame• Next Frame• DTC• Previous DTC - Chg• Next DTC - Chg




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Student WorkbookSystem Information (I/M Flags)The System Information (I/M Flags) screen allows you to view the statusof several PCM OBD II diagnostic tests (Figure 15-20). The Yes/Noparameter tells you whether the diagnostic test has run on each system.This parameter does not indicate the pass/fail status of the on-boarddiagnostic test, rather it shows that the test has run (YES) or has not run(NO). Each data parameter in this display is known as an I/M Flag.The System Information (I/M Flag) can be a valuable feature in thefollowing situations:• After making a repair on a system involving System Information (I/M

Flags), it is important to verify your repair by operating the vehicle in away to cause the I/M Flag to set (to YES). If Yes is displayed and noMIL, DTC, Freeze Frame, or Fail Record, related to the concern arepresent, the repair is successful.

• Some areas of the U.S. that require emission testing of vehicles mayrequire an owners vehicle to pass an I/M - OBD II test. In some casesthese tests may require the state I/M testers to scan the vehicle's PCMto view the I/M Flags. If "NO" is displayed for any I/M Flag, the statetesters may reject the vehicle (not issue registration or tags).

Important:When a System Information (I/M Flag) is set to Yes, this simply indicatesthat the PCM on-board diagnostic for that system has run. It does notindicate the pass/fall status of that system. You must refer to other Tech 2information to determine the pass/fail status of each system.To set all I/M Flags to "Yes," the vehicle must be operated in a mannerthat satisfies the enable criteria of all of the I/M Flag diagnostics. GeneralMotors OBD II course #16030.02 provides additional detail on this topic.

Figure 15-20, Inspection/Maintenance Flags




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Student WorkbookThe Service Programming SystemThe Service Programming System (SPS) allows you to program areplacement controller or update the flash calibration stored in an onboardcontroller (e.g. ECM, PCM, VCM). When troubleshooting a driveabilityconcern, diagnosis may call for reprogramming the controller with newerflash calibration information that addresses the concern.There are two SPS methods:• Remote Programming• Off-Board Programming

Remote SPS ProgrammingThe Remote SPS method is a three step process. The following threeSPS procedures are only an overview of the process.1. Connect the scan tool to the vehicle and obtain information from the

controller (Figure 15-17).2. Connect the scan tool to the PC and download a new calibration file

from the to the scan tool's memory (Figure 15-17).3. Re-connect the scan tool to the vehicle and upload the new calibration

file to the controller.

Off-Board ProgrammingOff-Board Programming is used when a reprogrammable control modulemust be programmed away from the vehicle. This method requires theuse of an Off-Board Programming Adapter (OBPA), J 41207-B.Notice:Prior to performing SPS, it is important to heed the following precautions:1. Ensure that the Tech 2 and the terminal are both equipped with the

latest software.2. Ensure that the vehicle battery is fully charged. Battery voltage for SPS

should be between 12 and 17 volts. DO NOT USE A BATTERYCHARGER WHILE PROGRAMMING.

3. Ensure that the cable connections are secure. A disconnected cablecould cause controller failure.




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Student WorkbookTool OptionsThe Tool Options choice from the Main Menu allows the technician tomake adjustments to the basic functions of the Tech 2 (Figure 15-19). ToolOptions include:• Set Clock • Set Training Center Mode• Set Screen Contrast • Programming Tech 2• Set Units • Set Communication By-Pass Mode• Self Test • Make Duplicate PCMCIA CardThe clock, contrast and units choices will set a new default value for theTech 2. The default value is what the Tech 2 will use when powering upeach time.Set Clock allows the date and time of the Tech 2 to be reset. The setting isnot saved unless the Set Clock soft key is pressed prior to exiting thefunction.Set Screen Contrast allows for screen contrast changes which will beretained after power down of the Tech 2. Follow the Tech 2 screeninstructions to set the contrast default. Contrast may still be set duringeach individual power up of the Tech 2 using the shift and arrow keys.The Set Units menu selection will allow the technician to change thedefault for units to be either English or Metric.Self Test allows the technician to run tests which will help to diagnosepossible faults with the Tech 2 itself. Because the Tech 2 runs the PowerOn Self Test (POST) at each power up, there is generally no need to usethe Self Test functions. If the POST finds a fault, the technician may go tothe Self Test menu choice and review the POST results.The "Programming Tech 2" selection gives the technician instructions onhow to update the Tech 2 with the latest software.The "Set Communications By-Pass Mode" feature allows the user tonavigate to Tech 2 data screens without being connected to live vehicledata, and is generally used as an engineering development tool.The "Make Duplicate PCMCIA Card" selection (Figure 3-20) allows atechnician to copy the contents of a PCMCIA Card to another PCMCIACard. This method of updating is usually faster than updating from aTechline Terminal.

Important:"Set Training Center Mode" is not needed for diagnosis at the dealership.This mode is only used at the GM Training Centers for training purposes.




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Student WorkbookThe Tech 2 Update ProcedureThe Software Download function of TIS2000 allows updating of the Tech 2 scantool with the latest software. TheSoftware Download function will transfer(download) updated software from thePC to the scan tool.

Standard UpdateTo perform a standard Tech 2 update:1. Connect the scan tool to the PC

using the RS 232 cable (refer toFigure 15-21).

2. Power up the scan tool using theAC power supply that came withthe tool (refer to Figure 15-22).

3. At the PC, start TIS 2000.4. From the TIS 2000 Main screen,

select the Software Download icon(refer to Figure 15-22).

Figure 15-21, Cable Connections

Figure 15-22, TIS 2000 Main Screen




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Student Workbook

Figure 15-23, Select Tech 2 for Download

Figure 15-24, Confirm Software Change

6. The PC will display a ConfirmSoftware Change screen(Figure 15-24) showing whatthe Tech 2 currently containsand what it will contain afterthe download. Click Next tocontinue.

5. At the Select Tool forDownload screen, highlightand verify your selection(Figure 15-23).• Standard installs the

newest software onto thescan tool.

• Custom allows backdatingor installing of non-NAOsoftware onto the scantool.

After confirming the selection,click on the Next button. Amessage will appearindicating the PC is readingthe contents of the diagnostictool.




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Student Workbook

Figure 15-25, Software Download Progress

Figure 15-26, Download Complete

7. A Performing the SoftwareDownload screen will appear(Figure 15-25). It tracks thestatus of the download.

8. When the download iscomplete, a DownloadFinished screen appears(Figure 15-26). Click on theClose button to close theapplication.

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